Add metadata for the RHS to the production schema for line number support.
Merge pull request #52 from palletops/feature/throw-on-missing-rhs

Add exceptions for missing => in defrule
* src/main/clojure/clara/rules.clj
  (make-query): Added
  (make-rule): Added

* src/main/clojure/clara/rules/compiler.clj
  (mk-session): Print out the names of the production rules loaded.
changes
Add exceptions for missing =>